Mercurial > sdl-ios-xcode
diff docs/man3/SDL_BlitSurface.3 @ 55:55f1f1b3e27d
Added new docs for SDL 1.2.1
author | Sam Lantinga <slouken@lokigames.com> |
---|---|
date | Sun, 10 Jun 2001 19:31:57 +0000 |
parents | 74212992fb08 |
children | e5bc29de3f0a |
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--- a/docs/man3/SDL_BlitSurface.3 Sun Jun 10 18:39:47 2001 +0000 +++ b/docs/man3/SDL_BlitSurface.3 Sun Jun 10 19:31:57 2001 +0000 @@ -1,4 +1,4 @@ -.TH "SDL_BlitSurface" "3" "Mon 12 Mar 2001, 01:04" "SDL" "SDL API Reference" +.TH "SDL_BlitSurface" "3" "Sun 10 Jun 2001, 19:41" "SDL" "SDL API Reference" .SH "NAME" SDL_BlitSurface\- This performs a fast blit from the source surface to the destination surface\&. .SH "SYNOPSIS" @@ -18,11 +18,26 @@ .PP The blit function should not be called on a locked surface\&. .PP -.RS -\fBNote: +The results of blitting operations vary greatly depending on whether \fBSDL_SRCAPLHA\fP is set or not\&. See \fISDL_SetAlpha\fR for an explaination of how this affects your results\&. Colorkeying and alpha attributes also interact with surface blitting, as the following pseudo-code should hopefully explain\&. .PP -The results of blitting operations vary greatly depending on whether \fBSDL_SRCAPLHA\fP is set or not\&. See \fISDL_SetAlpha\fR\&. -.RE +.nf +\f(CWif (source surface has SDL_SRCALPHA set) { + if (source surface has alpha channel (that is, format->Amask != 0)) + blit using per-pixel alpha, ignoring any colour key + else { + if (source surface has SDL_SRCCOLORKEY set) + blit using the colour key AND the per-surface alpha value + else + blit using the per-surface alpha value + } +} else { + if (source surface has SDL_SRCCOLORKEY set) + blit using the colour key + else + ordinary opaque rectangular blit +}\fR +.fi +.PP .SH "RETURN VALUE" .PP If the blit is successful, it returns \fB0\fR, otherwise it returns \fB-1\fR\&. @@ -42,4 +57,4 @@ .SH "SEE ALSO" .PP \fI\fBSDL_LockSurface\fP\fR, \fI\fBSDL_FillRect\fP\fR, \fI\fBSDL_Surface\fR\fR, \fI\fBSDL_Rect\fR\fR -...\" created by instant / docbook-to-man, Mon 12 Mar 2001, 01:04 +...\" created by instant / docbook-to-man, Sun 10 Jun 2001, 19:41